Tuesday, September 29, 2015

Sanding Of Canopy Fairing Begins

Yesterday, after the morning rains subsided, the RV-12 was rolled out of the hangar and the canopy fairing sanding process started in earnest. The sanding process began with 80 grit sand paper. In the area of the canopy frame arms, it was more for removing rough edges and to prepare it for a heavy brushing of resin.
Sanding the lay-up on the canopy frame’s arm down to smooth up the rough edges.

The main area of focus (and the most time consuming) was the area where the fiberglass lay-up meets the red electrical tape on the canopy.  I used a piece of 2" diameter PVC pipe along with a small wooden block to sand down to the level of the tape (which is still the second tape layer). A lot of care was used during the sanding process not to cut through the tape … yet making a smooth transition to the tape.
Using a 2" diameter PVC pipe and 80 grit sandpaper to carefully sand down the resin in the area of the red tape without cutting into the red tape.
Most of the sanding is almost done to prepare the lay-up for the heavy coating of resin that will be brushed over the entire lay-up.

For the next step, Van’s instructs the builder to remove the second layer of red tape and sand down even to the first layer of red tape using 150 grit sandpaper. This is followed by brushing on a heavy layer of resin over the entire lay-up … this will be used as a base coat for fillers to smooth out the lay-up. Unfortunately, it rained the entire day today, so was not able to roll the fuselage outside and remove the second layer of red tape and do the light sanding down to the first layer of tape per the instructions. Hopefully the weather will cooperate tomorrow so the sanding can be completed and the entire lay-up covered with a heavy layer of resin.

Saturday, September 26, 2015

Canopy Fairing Busted Lose & Bolt Holes Opened

After a day away from the RV-12 giving Bernie a hand with a yard project, made it out to the hangar yesterday and was able to verify the fairing lay-up did not permanently glue the canopy frame to the fuselage. At this point, Van’s would have the builder remove the canopy from the fuselage and do the sanding on the workbench. Since I really do not want a bunch of fiberglass glass dust inside the hangar, decided I will roll the fuselage outside and do most of the sanding there.

Some builders have had trouble breaking the canopy lay-up free from the fuselage ... so prior to sanding and filling, decided it best to first make sure the canopy fairing lay-up could be broken free from the fuselage. The canopy was unlatched and since the rear window is still out, it was easy to just reach inside and flex the left side of the canopy frame’s rear bow upwards a few times using progressively more force until there was a dull "pop" sound. Walked around to the right side of the aircraft and repeated the process and was rewarded by another "pop' as the right side broke free. My sigh of relief was accompanied with a big smile … the use of a very thin film of Vaseline as a release agent was a good call.

I did not attempt to open the canopy all the way for fear the metal would get dented. Once the fairing has been sanded and low spots filled, the canopy frame will need to come off so the fairing lay-up can be trimmed back to match the pattern supplied by Van’s. To do this the canopy frame pivot bolts will need to be removed … and to do that, they need to be exposed. Decided it best not to use the Van’s pattern and rely on blind faith … so I went “high tech” and used a magnet to locate the heads of the bolts. Worked great!
Getting “high tech” and using a magnet in lieu of the paper template to locate the canopy frame’s pivot bolts. A circle was traced around the magnet to mark the bolt location.

Now knowing where the bolts are, the big question is how best to get to them? I decided to use a Dremel with a sanding drum to cut a divot in the fiberglass by holding the edge of the drum at a 45 degree angle. Next a #19 drill bit was turned by hand a few times until I could see the metal of the bolt, then the sides were opened up a little using a #12 bit by hand to shave the fiberglass and open the hole up enough for the next Dremel tool which was a small carbide coated cylinder.  If following my foot steps here, when using the carbide coated cylinder - use a slow speed on the Dremel, plus use very little cutting pressure and continually move the bit around. The reason for all this is if spinning too fast or left in one spot too long, the epoxy resin will melt from the friction and quickly clog the fine abrasive on the bit.
Using the Dremel outfitted with a carbide cutter cylinder to open up the bolt hole so a 1/4" sanding drum can finish the job.
The Dremel with the carbide cutting cylinder and the 1/4" sanding drum.

The above procedure was used until the hole was opened up enough to accommodate the Dremel’s small sanding drum. The sanding drum was extended over the edge of the rubber so the screw at the tip of the sanding drum would not scrape on the bolt head. The sanding drum did a good job of opening the hole the rest of the way … it was a piece of cake. Did switch to a larger 1/2" sanding drum as the hole got larger … but that really was not necessary.
The bolt hole needs to be made just a little larger to allow a socket to slip into the hole.
The bolt hole is now opened up enough to allow a socket to be inserted onto the canopy frame pivot bolt.
Moved over to the right side and used the same procedure to expose the bolt and enlarge the hole so a socket would slip over the bolt. Knowing what to do made the right side much faster to complete. Both bolt holes will be fine tuned when the canopy is removed for cutting. The holes will be sanded out to the piece of aluminum tubing that was added to make a nice tunnel for the bolt.

Wednesday, September 23, 2015

Tweaking The Canopy Fairing Lay-up

Today, I decided to add a couple of layers of cloth to the left and right side of the canopy fairing lay-up in the area where the glass cloth got depressed above the canopy frame arms. The reason being is so filler will not need to be laid on so thick in this area. Did not want to waste a full pump of epoxy resin for such small pieces, so taking the advice of builder Bob in Wisconsin, I made plunger stops for the pumps so they only depress half of their full range … thus dispensing half the amount of resin and hardener. It would be a nice touch if West Systems would provide plunger stops with the dispenser kit for those small batches that are so often needed … because I see a few small batches of micro filler on the horizon.
Wooden stops made for the resin and hardener pumps to only allow half the normal amount of resin and hardener to be dispensed.

After making the plunger stops, they were quickly put to use. I used some tracing paper and made a template for cutting strips of cloth to help fill the depressions above the canopy frame arms. A small batch of epoxy resin was mixed and two strips of cloth were applied to the depression and covered with peal-ply. It looks like the remaining imperfections on the left side can be filled with filler but the right side may benefit from one additional layer.
Two narrow plies of glass cloth were applied to the depressions on both sides and covered with peal-ply. Here on the right side it is hard to see, but there is still a little dip under the peal-ply in the area between my fingers.

Of note: I should have been wearing the above T-shirt last Friday during phase one of the canopy lay-up.

Monday, September 21, 2015

RV-12 Canopy Fairing Lay-up Completed!

It was a good day at the office - no surprises, no problems and no mistakes … and the resin pump even cooperated.  Bernie and Mike K. came by the hangar and pitched in with the canopy fairing bridge lay-up. The three of us made an assembly line to knock out laying up the remaining ten plies of glass cloth that will make up the bridge connecting the left and right canopy arm lay-ups. Thanks guys for all the help …. it is truly much appreciated. Mike T. also came by as well and helped take some of the photos of our work activities ... thanks Mike that was much appreciated because I did not want to get near the camera with epoxy resin on my fingers.

As with the first ply on the canopy frame arms, the resin for the first layer of the canopy bridge lay-up was tinted black. After the first layer was wetted out on the work table, it was transferred to the canopy and smoothed out. Special care was taken to minimize the amount of sag in the gap between the canopy and upper fuselage skin. Once happy with the shape, the first layer was allowed to cure (for a long time) until the resin had set up to the point it was getting stiff but still tacky.
Bernie took on the roll of the “mixologist”.
Stippling epoxy resin dyed black into the glass cloth for the first layer of the canopy bridge lay-up.
First layer of the canopy bridge lay-up in position, but prior to removing the sag between the upper fuselage skin and canopy.

This time we deviated from Van’s plans and DID NOT place the remaining layers on dry and then stipple resin into them. Instead, all the remaining layers were wetted out with resin while on plastic wrap, wiped with a squeegee to remove excess resin, plastic wrap trimmed, then the wet cloth/plastic wrap was transferred to the canopy, cloth carefully positioned and the plastic wrap removed. After removing the plastic wrap, the positioning of the layer of glass cloth was tweaked and then the air bubbles were gently stippled away with extra care not to stipple hard straight down into the area of the gap. The results were outstanding.
Mike and I wetting out the second layer of glass cloth … only eight more to go.

Van’s drawing showing the positioning of the ten layers leaves a bit to be desired … the lines are drawn so closely together it is very hard to identify the lines for each layer without either young eyes or a magnifying glass. Since we are all geezers, we chose the magnifying glass route.
"Inspector" Mike using a magnifying glass to verifying the positioning for the next layer of glass cloth.
I’m adjusting the positioning of a layer of glass cloth as Bernie mixes up another batch of epoxy and Mike had just finished cleaning epoxy resin off the scissors.

By the time we got past the second layer, we had a good system going. While I was fine tuning and stippling air bubbles out of the current lay-up, Bernie mixed the next batch of epoxy resin and Mike set up a new piece of plastic film and placed the next glass cloth layer on the launching pad. For those builders curious about the amount of resin mixture used … approximately one pump of resin and hardener was enough to wet out each of the wider pieces of glass cloth and a few of the narrow pieces.
Bernie and Mike wetting out the tenth and final layer of glass cloth for the canopy bridge lay-up.

One of the down sides about using pallet wrap is ... not if, but when, it sticks to itself … it is really hard to separate it with gloves on. We were able to mitigate this mess by trimming the plastic wrap very close to the edge of the glass cloth.
Remember what I mentioned about the plastic wrap clinging to itself? It is not so easy to get unstuck.
Nope – not a May Day parade … just Bernie and I  transferring the final lay-up to the canopy.
Bernie and I carefully placing the final lay-up onto the canopy.
Pealing the plastic wrap away from the epoxy resin soaked glass cloth.

All the layers of glass cloth for the canopy bridge are cut to 36" and all need to be custom trimmed in place on the canopy.
Mike cutting the final layer of the canopy bridge lay-up to length while Bernie holds the cloth off the surface of the canopy fairing.
Putting the finishing touches on the final layer of the canopy bridge lay-up.
Completed canopy bridge lay-up before applying the peal-ply. All ten layers are in place.
Finished lay-up with peal-ply in place.

The plans state the radius of the transition from the canopy to the upper fuselage skin is supposed to be approximately 2" … so a piece of PVC pipe was located that has a 2" diameter to use as a gauge. All and all, the lay-up seems to be in the ball park as can be seen in the photo below.
The transition is close to the 2" radius suggested by Van’s.

Also should mention some of the scraps were used to build up the depressions above the canopy arms … doing this will require less filler. Although the canopy lay-up is finished, there will be many hours of sanding and filling ahead. Oh joy!